Nano-Dimensional Carbon Nanosphere Supported Non-Precious Metal Oxide Composite: A Cathode Material for Sea Water Reduction.

Generation of hydrogen fuel at cathode during the electrolysis of seawater can be economically beneficial considering the vast availability of the electrolyte although it faces sluggishness caused by the anode reactions. In this regard a carbon nanosphere-protected CuO/CoO (CCuU) composite was synthesized through heat treatment and was used as the cathode material for electrocatalytic seawater splitting. CCuU showed a significantly low overpotential of 73 mV@10 mA cm, Tafel slope of 58 mV dec and relatively constant activity and morphology over a long time electrocatalytic study.

Designing an intriguingly fluorescent N, B-doped carbon dots based fluorescent probe for selective detection of NO ions.

Low-cost nitrogen and boron-doped carbon nanodots (CPAP-CDs) with a high quantum yield (64.07%) were synthesized through a facile hydrothermal treatment. The obtained CPAP-CDs exhibited wide absorption, strong fluorescence, and pH-dependent behavior.

High quantum yield aminophenylboronic acid-functionalized N-doped carbon dots for highly selective hypochlorite ion detection.

High quantum yield 3-aminophenylboronic acid-functionalized nitrogen-doped carbon dots (GAAP-CDs) were fabricated using a simple hydrothermal route and used as a sensing probe for toxic hypochlorite (ClO). The as-synthesized GAAP-CDs showed absorption peaks at 252, 297, and 370 nm and an emission peak at 375 nm with an excitation wavelength of 310 nm. The quantum yield of GAAP-CDs reached 58.

Simple paper-based colorimetric and fluorescent glucose sensor using N-doped carbon dots and metal oxide hybrid structures.

A new strategy for the fluorescent and colorimetric sensing of hydrogen peroxide (HO) and glucose based on the metal oxide - carbon-dot hybrid structure was investigated. The sensing system is related to the catalytic oxidation reaction of glucose-by-glucose oxidase (GOx) to HO. In this study, a metal oxide hybrid with nitrogen-doped carbon dots (MFNCDs) that showed intrinsic peroxidase-like activity was synthesized and used as a catalyst instead of GOx to oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to blue-emitting oxidized TMB (oxTMB) in the presence of hydrogen peroxide (HO).

Uncovering the actual inner-filter effect between highly efficient carbon dots and nitroaromatics.

High performance sensors can be produced by adequately designing the chemical structure and uncovering the actual detection mechanism. In this study, a fluorescent probe was synthesized for various nitroaromatic molecules, including stereochemically varied nitrophenols and nitroaniline. A systematic investigation of the influence of various analytes on the luminescence behavior of the as-synthesized carbon dot (CDs) revealed the inner-filter effect to be the major detection mechanism.

ZnO-Associated Carbon Dot-Based Fluorescent Assay for Sensitive and Selective Dopamine Detection.

This paper presents a simple and highly efficient method for dopamine detection using water-soluble carbon dot nanoparticles. The ZnO-associated carbon dots (CDZs) were synthesized using a green chemical strategy. An examination of the effects of biomolecules on the fluorescence of CDZs revealed selective dopamine-induced quenching.

One-Pot Fabrication of Perforated Graphitic Carbon Nitride Nanosheets Decorated with Copper Oxide by Controlled Ammonia and Sulfur Trioxide Release for Enhanced Catalytic Activity.

In this article, we have judiciously interfaced copper oxides with graphitic carbon nitride (g-CN) from thermal reaction of melamine and copper sulfate in a one-pot protocol and manipulated the perforated sheet morphology thereafter. The CCN- ( = 30, 40, 50, 60, and 70, depending on the wt % of CuSO·5HO) nanocomposites were prepared by homogenously mixing different percentages of CuSO·5HO with melamine from a solid-state thermal reaction in a furnace in air. Drastic lowering of CuSO decomposition temperature due to Cu(II)-amine complex formation and subsequent reduction of Cu(II) species by in situ produced ammonia (NH) resulted in the production of CuO and catalytic amount of CuO, homogeneously dispersed within the perforated g-CN nanosheet.

Blue emitting nitrogen-doped carbon dots as a fluorescent probe for nitrite ion sensing and cell-imaging.

This study examined the efficiency of pH-dependent, fluorescent carbon dots for the sensing of hazardous anions in aqueous media and cell imaging. The nitrite anion, an important water-soluble element for environmental and biological systems, requires continuous monitoring because a high concentration can affect the systems severely. The as-synthesized carbon dots efficiently detected the nitrite anion in aqueous solution through a fluorescent 'Turn Off' phenomenon.

Benzophenone assisted UV-activated synthesis of unique Pd-nanodendrite embedded reduced graphene oxide nanocomposite: a catalyst for C-C coupling reaction and fuel cell.

In this work we report the use of benzophenone (BP) for the synthesis of a palladium (Pd) embedded on reduced graphene oxide (rGO) nanocomposite (Pd/rGO) using a simple aqueous solution and UV irradiation. The simple and facile evolution of thermodynamically unstable branched Pd(0) nanodendrites was achieved by BP photoactivation, circumventing the growth of more stable nanomorphologies. The synthesis of Pd(0)-embedded rGO nanosheets (PRGO-nd) was made possible by the simultaneous reduction of both the GO scaffold and PdCl by introducing BP into the photoactivation reaction.

Evolution of Silver-Mediated, Enhanced Fluorescent Au-Ag Nanoclusters under UV Activation: A Platform for Sensing.

Here, we report the synthesis of dopamine (DA)-mediated Au-Ag bimetallic nanoclusters in aqueous solution under UV activation. The success story emerges from monometallic fluorescent nanocluster evolution from photoactivation of gold as well as silver precursor compounds along with DA. The intriguing fluorescence property of the nanocluster relates to facile incorporation of Ag in Au, showing a 6-fold enhancement of the emission profile than simply DA-mediated Au nanoclusters.

Carbon dot-Au(i)Ag(0) assembly for the construction of an artificial light harvesting system.

Artificial light harvesting systems (LHS) with inorganic counterparts are considered to be robust as well as mechanistically simple, where the system follows the donor-acceptor principle with an unchanged structural pattern. Plasmonic gold or silver nanoparticles are mostly chosen as inorganic counterparts to design artificial LHS. To capitalize on its electron accepting capability, Au(i) has been considered in this work for the synergistic stabilization of a system with intriguingly fluorescing silver(0) clusters produced in situ.

Solvent Polarity-Dependent Behavior of Aliphatic Thiols and Amines toward Intriguingly Fluorescent AuAgGSH Assembly.

Highly stable fluorescent glutathione (GSH)-protected AuAg assembly has been synthesized in water under UV irradiation. The assembly is composed of small Ag/Ag clusters. These clusters gain stability through synergistic interaction with Au(I) present within the assembly.

Fluorescence enhancement via varied long-chain thiol stabilized gold nanoparticles: A study of far-field effect.

Metal enhanced fluorescence of carbon dots has been reported in aqueous solution. Moderately fluorescing carbon dots (λ=360nm and λ=440nm) of 6-8nm diameters (CDA) have been synthesized from freshly prepared aqueous ascorbic acid solution under modified hydrothermal treatment. The CDA fluorescence is quenched at the close proximity with gold nanoparticles (AuNPs).

Remarkable Facet Selective Reduction of 4-Nitrophenol by Morphologically Tailored (111) Faceted CuO Nanocatalyst.

In this work, we have disclosed the facile syntheses of morphologically diverse CuO nanoparticles using our laboratory designed modified hydrothermal reactor employing low-cost copper (II) acetate precursor compounds. The reaction conditions dovetail the effect of ethylene glycol (EG) and glucose to exclusively evolve the morphology tuned CuO nanomaterial at different pHs. The morphology tuning produces octahedron (Oh), dwarf hexapod (DHP), and elongated hexapod (EHP) CuO structures only with the optimized reagent concentrations.

Boron Precursor-Dependent Evolution of Differently Emitting Carbon Dots.

Attention has been directed toward electron-deficient boron doping in carbon dots (CDs) with the expectation of revealing new photophysical aspects in accordance with varying amounts of boron content. It has been emphatically shown that boron uptake in CDs varies with different boron precursors evolving altered emissive CDs. Boron doping in CDs causes definite surface defect due to the generation of electron-deficient states.

One pot synthesis of intriguing fluorescent carbon dots for sensing and live cell imaging.

We report a simple one-pot synthesis of highly fluorescent carbon dots (CDs) via modified hydrothermal (MHT) treatment of alkaline solution of dopamine and cysteine. These CDs (λex=320 nm, λem=390 nm, and quantum yield ∼ 5.1%) are of ∼ 2-3 nm in diameter.

Silver nanoparticle anchored carbon dots for improved sensing, catalytic and intriguing antimicrobial activity.

Fluorescent carbon dots (NSCDs) with a size of ∼5 nm (λex = 320 nm and λem = 386 nm) have been synthesized under reflux from an alkaline mixture of dopamine and cysteine. The synthesized NSCDs are hybridized with in situ generated silver nanoparticles (AgNPs) obtained by mixing AgNO3 at room temperature. NSCDs enrich the plasmonic bands of AgNPs due to the localized surface plasmon resonance (LSPR) effect.

Orange-red silver emitters for sensing application and bio-imaging.

Highly fluorescent Au(I)@Ag particles (emission maximum at 635 nm) have been obtained from a mixture of AgNO3, HAuCl4 and glutathione. Au(I)@Ag particles containing Ag2 and Ag3 clusters are produced when the reaction mixture is subjected to a modified hydrothermolysis (MHT) reaction. The silver clusters make the solution intensely fluorescent and the Au(I) moiety provides long term stability to the silver clusters by withdrawing electron density from the silver clusters.

Intriguing cysteine induced improvement of the emissive property of carbon dots with sensing applications.

A simple fluorometric technique has been adopted for cysteine (Cys) sensing in alkaline medium down to the nM level. The huge fluorescent signal of the solution is a consequence of fluorescent carbon dots (CDs) produced in situ from modified hydrothermal (MHT) reaction between Cys and dopamine (DA). It has been observed that the inherent fluorescence of DA is drastically quenched in alkaline solution.

Biomolecule-mediated CdS-TiO2-reduced graphene oxide ternary nanocomposites for efficient visible light-driven photocatalysis.

We report an environmentally friendly synthetic strategy to fabricate reduced graphene oxide (rGO)-based ternary nanocomposites, in which glutathione (GSH) acts both as a reducing agent for graphene oxide and sulfur donor for CdS synthesis under modified hydrothermal (MHT) conditions. The report becomes interesting as pH variation evolves two distinctly different semiconducting nanocrystals of anatase/rutile TiO2 and hexagonal yellow/cubic red CdS, and their packaging makes them suitable photocatalysts for dye degradation. Herein, a titanium peroxo compound, obtained from commercial TiO2, is hydrolyzed to TiO2 nanostructures without any additives.

Green synthesis of highly fluorescent Au(I)@Ag2/Ag3-thiolate core-shell particles for selective detection of cysteine and Pb(II).

Giant Au(I)@Ag2/Ag3-thiolate clusters with strong fluorescence (λex 400 nm, λem 564 nm, and quantum yield 8.3%) have been prepared in aqueous medium from glutathione and corresponding precursor salts at neutral pH under sunlight. An intriguing synergism between Au(I)core and Ag(0)shell imparts long-term stability to the fluorescent giant clusters (synthesized with a chemically green method) due to drifting of electron density towards core from shell.

Selective dopamine chemosensing using silver-enhanced fluorescence.

Condensation product of salicylaldehyde and 1,3 propylenediamine becomes a diiminic Schiff base, which is oxidized by AgNO3 in alkaline solution, and in turn, stable Ag(0) is produced at room temperature. Under this condition, the solution exhibits intense silver nanoparticle enhanced fluorescence (SEF) with the λ(em) at 412 nm. Dopamine is selectively detected down to the nanomolar level via exclusive fluorescence quenching of the SEF.

Morphology controlled synthesis of SnS₂ nanomaterial for promoting photocatalytic reduction of aqueous Cr(VI) under visible light.

A mild, template free protocol has been demonstrated for SnS2 nanoflake formation at the gram level from SnCl2 and thioacetamide (TAA). The SnS2 nanoflakes congregate to nanoflowers and nanoyarns with variable TAA concentrations. BET measurements reveal that the synthesized nanomaterials are highly porous having very high surface area, and the nanoflower has higher surface area than the nanoyarn.

Photoproduced fluorescent Au(I)@(Ag2/Ag3)-thiolate giant cluster: an intriguing sensing platform for DMSO and Pb(II).

Synergistic evolution of fluorescent Au(I)@(Ag2/Ag3)-thiolate core-shell particles has been made possible under the Sun in presence of the respective precursor coinage metal compounds and glutathione (GSH). The green chemically synthesized fluorescent clusters are giant (∼600 nm) in size and robust. Among all the common water miscible solvents, exclusively DMSO exhibits selective fluorescence quenching (Turn Off) because of the removal of GSH from the giant cluster.